With the Interurban Vehicle – IUV for short – DLR is showing what medium- and luxury-class vehicles could look like in the future.
The focus is on zero-emission mobility, automation, safety and comfort.
The IUV is a fuel cell plug-in hybrid, i.e. it combines a fuel cell, hydrogen tank and battery.
The concept also shows the new freedom that automation enables in terms of vehicle design and architecture.
Focal points: transport, intelligent mobility, hydrogen

With the Interurban Vehicle (IUV) , the German Aerospace Center (DLR) has developed a forward-looking concept for medium- and luxury-class vehicles. It is five meters long, two meters wide and can accommodate five people. The IUV combines fuel cells, batteries and new approaches to energy management. It should enable emission-free and comfortable driving over long distances of up to 1,000 kilometers. Autonomous driving functions relieve the driver and allow new freedom in the design of the interior. Thanks to the clever combination of different lightweight construction approaches, the IUV with energy storage weighs less than 1,600 kilograms when empty. At the same time, it offers a very high security standard. "For the project, we set up the IUV as a rollable body demonstrator. This demonstrator gives a first impression of what the vehicle could look like in practice. At the same time, with the help of the demonstrator, we were able to better develop, measure and test central components and technologies on test benches. It also shows which aspects we can further develop and implement with partners from industry and research in the future," says project manager Sebastian Vohrer from the DLR Institute for Vehicle Concepts in Stuttgart .

New construction methods, innovative materials and functional integration

A lightweight vehicle structure is key to keeping energy consumption low and range high. "The body shell of the IUV weighs only 250 kilograms, around a quarter less than is currently the case in this vehicle segment," says DLR scientist Vohrer. In order to achieve this goal, different lightweight construction methods were implemented. In addition, the body of the IUV consists to a large extent of fiber-reinforced plastics. In some cases, structures made of aluminum or sandwich materials are also used - especially where the components have to be very rigid in a crash and have to absorb a lot of energy. Sandwich materials combine, for example, a top layer made of fiber composite material with a light core made of plastic foam or sustainable materials such as balsa wood. The team built selected components of the IUV as prototypes and tested them in crash tests, for example, in order to check the calculations and simulations previously made on the computer. This included the side skirts below the side doors. It is a particularly important structure and is intended to protect the hydrogen tank in the vehicle floor and the occupants in the event of a side impact. Because the IUV does not have a center pillar, which in conventional bodies connects the floor and roof of the vehicle and serves as a crash element. Without a central column, large door openings are also created. In conjunction with sliding doors that open in opposite directions, they make getting in and out particularly easy. Wherever possible, the DLR researchers have also worked with functional integration - another approach to lightweight construction: "Structures fulfill several functions, for example the floor structure not only supports all the superstructure of the vehicle, but also conducts electricity or data at the same time. So you can sometimes do without additional cable lines and thus save more weight overall,” explains Vohrer. https://www.youtube.com/watch?v=mevVumy0xUQ

Emission-free on the road: fuel cell, battery and smart energy management

The IUV is designed as a fuel cell plug-in hybrid. It combines a fuel cell with an output of 45 kilowatts, a 700 bar hydrogen pressure tank and a battery with a capacity of 48 kilowatt hours. With this configuration, the IUV has a total range of up to 1,000 kilometers. The electric motors with a total output of 136 kilowatts accelerate the vehicle to up to 180 kilometers per hour. The refueling process at a hydrogen filling station takes about as long as with conventional drives. The battery can also be charged separately. The fuel cell is in the front end and the battery is in the rear of the five-meter-long vehicle. The hydrogen tank is built into the underbody and holds around 7.5 kilograms of hydrogen. The DLR team from the Institute for Vehicle Concepts also took a close look at the topic of energy management. Because the more electrification in vehicles increases, the more efficiently all electricity, heating and cooling processes must be designed. Otherwise there is a risk of losses in range or in comfort functions such as air conditioning, information and entertainment systems. For the IUV, the researchers took a closer look at metal hydride storage, among other things. This new type of storage is being investigated and developed in close cooperation with the DLR Institute of Technical Thermodynamics. With their help, part of the pressure difference between the hydrogen tank at 700 bar and the fuel cell at five bar can be used,

Autonomous driving enables more flexibility and comfort in the interior

During the work for the IUV, the DLR scientists also examined how autonomous driving affects the vehicle concept and vehicle architecture. For this, they assumed a high degree of automation (SAE Level 4). The car drives itself all the time. Only when it can no longer cope with a task does it ask the driver to take control again. "Especially on long journeys, automation can significantly relieve drivers. At the same time, it enables us to design the interior of the vehicle more openly and flexibly," says project manager Sebastian Vohrer. The IUV team has developed different designs and evaluated them for their functional and technical feasibility. One result is the seating arrangement of the IUV, which can be variably adapted to the driving mode: the two front seats can be rotated. In autonomous mode, the occupants can also sit with their backs to the direction of travel. The strict separation of the rows of seats is abolished and a common communication space is created. The air conditioning concept specially developed for the IUV adapts to the interior and the respective occupants. It is no longer controlled centrally via the dashboard. Instead, each passenger can regulate the air conditioning individually via interfaces in the roof liner - similar to airplanes. The air conditioning concept specially developed for the IUV adapts to the interior and the respective occupants. It is no longer controlled centrally via the dashboard. Instead, each passenger can regulate the air conditioning individually via interfaces in the roof liner - similar to airplanes. The air conditioning concept specially developed for the IUV adapts to the interior and the respective occupants. It is no longer controlled centrally via the dashboard. Instead, each passenger can regulate the air conditioning individually via interfaces in the roof liner - similar to airplanes.

Hydrogen Fuel Cell Hybrid Plug in Vehicle Drives Up to 1,000Km's